Bone-activity stimulation apparatus and method

ABSTRACT

A method of increasing bone mass throughout the body of a user. The method may include the steps of obtaining a distributor comprising a plurality of electromagnetic coils, obtaining a controller comprising a processor and a memory device, operably connected to one another, the memory device storing code executable by the processor, selecting a source of electrical current, connecting the source to the controller, and positioning a user proximate the distributor. The method may further include controlling, by the controller in accordance with the code, delivery of electrical current sequentially and exclusively to each coil of the plurality of electromagnetic coils to generate a magnetic field extending into the user.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 60/867,424 filed Nov. 28, 2006, which isincorporated by reference herein.

BACKGROUND

1. The Field of the Invention

This invention relates to electromagnetic simulation of bone stress, andmore particularly to methods and apparatus to stimulate or otherwiseinduce electrical activity in bones of a subject in order to elicit apositive response such as natural generation of increased bone density.

2. The Background Art

Human tissues are electrical apparatus. Likewise animal tissues areelectrical apparatus. A complex assembly of structure, chemistry, andelectrical connection controls and implements the activity, growth,healing, and other functions of living tissues of the animal kingdom.Manipulating the structures of tissues, whether soft tissue or bonetissue has been purview of the surgical portion of the medicalcommunity. Manipulation of chemistry has been the purview the drugportion of the medical community. Manipulation of the electricalactivities of body tissues has largely been left to the other twofields, surgical and chemical treatments.

There has been a development of an electrical treatment community in themedical field, particularly, dealing with electro-stimulation. However,many researchers in the field often claim a lack of understanding of thespecific phenomena that affect the correlation between electricalstimulation and organic functioning of live animal tissues.Nevertheless, electrical stimulation therapy has been used in bothinvasive and noninvasive systems for directly applying electricalpotential to stimulate a response.

Within the medical community, selected, time-varying electric andmagnetic fields have played an increasingly successful role in the careof several challenging medical problems, mainly fractures that havefailed to heal, in both children and adults, as well as chronic skinwounds. This progress has been made over the past decades.

Bioelectromagnetics is a term applied to a field developing in thebiological sciences and devoted to the interaction between livingorganisms and electromagnetic fields. Electrical phenomenon are inherentin most living organisms, and certainly in all animal organisms. Forexample bones, nerves, cartilage, muscle, and the like have beenconsidered to contain electrical connections and circuits for theirnormal operation. Accordingly, these electrical circuits can beinfluenced by external magnetic fields and electromagnetic fields.Publications indicate that electromagnetic fields operating atfrequencies below 300 hertz can influence biological functions. Somecontroversy exists regarding the mechanics of operation of theseinteractions.

Pulsed electromagnetic fields in medicine are not new. Static magnetsand electrical current have been used for years. In modern medicinehowever, it was in about the 1970's that the United States FDA approveda pulsed electromagnetic field device to assist in the healing ofnon-union fractures. Doctor C.A.L. Basset pioneered work leading to an80% success rate in the healing of non-union fractures without any sideeffects. Accordingly, therapy by pulsed electromagnetic fields isrecognized as effective in bone healing in the medical profession.

Meanwhile, additional detailed work has been done on a cellular level invitro and in vivo to evaluate the efficacy of pulsed electromagneticfields on bone density. Much of the work seems to be devoted toestablishing a specific biological mechanisms by which electromagneticfields couple to body chemistry and cellular activity.

With the magnetic fields induced by an MRI machine, molecular dipolesorient along the magnetic field lines. Once the magnetic field iscollapsed, the dipoles, actual physical molecules, rotate back to theiroriginal positions. The return to the original positions generatesanother magnetic pulse, which pulse is detected and used to reconstructin a computer an image of the tissues within the MRI field.

Thus, electromagnetic fields are not only known to affect body tissues,but body tissues themselves generate magnetic fields by their ownmotion, which magnetic fields are sufficiently strong to be detected andanalyzed by sophisticated signal processing in order to image tissuesand boundaries of tissues in the body.

Likewise, the bone structures of a body are known to have apiezoelectric characteristic. That is, they respond to stress bycreating an electrical potential. Likewise, however, since piezoelectricevents are symmetric. The application of electrical potential will thencause stress.

What is needed is a system implementing a method and apparatus forcoupling, non-invasively, an external electromagnetic field to the bodytissues that may provide electrical stimulation to bones.

It would be an advance in the art to improve non-invasiveelectro-stimulation by magnetic coupling of an electrical system outsideof a subject with the electrical system within a subject.

BRIEF SUMMARY OF THE INVENTION

In view of the foregoing, in accordance with the invention as embodiedand broadly described herein, a method and apparatus are disclosed inone embodiment of the present invention as including a distributorcomprising a plurality of electromagnetic coils. A controller maycontrol the operation of the distributor. The controller may include aprocessor and a memory device operably connected to one another, thememory device storing code executable by the processor. The controllermay be connected to a source of electrical current. During operation, auser may be positioned proximate the distributor (e.g., recline or lieover or below the distributor). The controller may then control,according to the code, delivery of electrical current to the coils. Inone embodiment, the controller may deliver current sequentially andexclusively to each coil to generate a magnetic field extending into theuser.

In accordance with the foregoing, an apparatus and method in accordancewith the invention implement a magnetic coil providing a magnetic fieldpenetrating a depth into a body sufficient to provide the designatedfield strength near a bone thereof. Accordingly, in an apparatus andmethod in accordance with the invention, the magnetic field acts inseveral ways.

First, as the field is established, and as it collapses, it iseffectively capable of inducing currents in circuits within the field.That is, whenever a circuit moves through a magnetic field, or amagnetic field moves across a circuit current is induced in the circuit.Thus, electrical circuits within the magnetic field generated by anapparatus will obey the law of physics and generate currents. Whether acircuit is formed of wire or of animal tissues, relative motion betweenthe circuit and the magnetic field will generate electrical currents inthe circuit.

Second, by generating a magnetic field, certain molecular dipoles incells within the body will undergo alignment or a tendency to align withthe field lines of the applied magnetic field. This provides an actualmechanical displacement stimulation.

Third, any generation of an electrical potential across a piezoelectricelement causes stress and typically strains at a “micro” level. Thisstress and strain is not distinguishable from “macro” level stresses andstrains corresponding to exercise.

Applicants observed in the use of electromagnetic stimulation for bonehealing of fractures in persons having poor bone repair function (e.g.,smokers, diabetics, poor circulation subjects, etc.) thatelectromagnetic stimulation aided both fracture healing and joinder offused constituents. However, following treatments effective to aid thebone healing, it was observed that even on the gross scale provided byX-ray images, an increase in bone density was apparent. Thus, Applicantsengineered a system to augment bone density increase over the entirebody. Applying a local electromagnetic field to one location of the bodyis not scalable by simply adding more devices, to treat the entire bodywith a mechanism of electromagnetic therapy.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing features of the present invention will become more fullyapparent from the following description and appended claims, taken inconjunction with the accompanying drawings. Understanding that thesedrawings depict only typical embodiments of the invention and are,therefore, not to be considered limiting of its scope, the inventionwill be described with additional specificity and detail through use ofthe accompanying drawings in which:

FIG. 1 is a schematic diagram of an apparatus in accordance with theinvention;

FIG. 2 is a schematic top plan view of a coil in the apparatus of FIG.1;

FIG. 3 is an end view of the coil of FIG. 2;

FIG. 4 is a plan view of one embodiment of the distributor portion ofthe apparatus of FIG. 1;

FIG. 5 is a schematic block diagram of one embodiment of a method inaccordance with the invention in a very simplified form;

FIG. 6 is a diagram of a side elevation view of the distributor of FIG.4 illustrating application of current and thus magnetic field as appliedto each coil in sequence in accordance with the invention;

FIG. 7 is a schematic block diagram of a method in accordance with theinvention for controlling treatment and recording therapy session data;

FIG. 8 is a schematic block diagram of a more sophisticated process inaccordance with the invention identifying various decisions and optionsas well as the effect of sensing as a means to control operation of anapparatus in accordance with the present invention;

FIG. 9 is a diagram of top plan view of a sensor-equipped distributorwith coils of various alternative configurations; and

FIG. 10 illustrates one example of an embodiment of a distributor of anapparatus in accordance with the invention, illustrating oneimplementation for a double bed cover, blanket, mattress-cover, or thelike.

DETAILED DESCRIPTION OF THE INVENTION

It will be readily understood that the components of the presentinvention, as generally described and illustrated in the drawingsherein, could be arranged and designed in a wide variety of differentconfigurations. Thus, the following more detailed description of theembodiments of the system and methods of the present invention, asrepresented in the drawings, is not intended to limit the scope of theinvention, as claimed, but is merely representative of variousembodiments of the invention. The illustrated embodiments of theinvention will be best understood by reference to the drawings, whereinlike parts are designated by like numerals throughout.

Referring to FIG. 1, an apparatus 10 in accordance with the inventionmay include a distributor 12 effective to distribute electromagneticflux through a subject or user. The distributor 12 may be controlled bya controller 14. The controller 14 may control current, duration,frequency, and the like for the electromagnetic flux provided by thedistributor 12 to a subject.

A power supply 16 may provide conditioned power to the controller 14.The power supply 16 may be adapted to receive electric power from apower source 18 such as conventional wall current, multi-phase currentavailable on distribution in a building, a generator, or the like. Inselected embodiments, a power supply 16 may convert alternating current(AC) received from the power source 18 into low voltage DC powersuitable for operating the controller 14. A power supply 16 may alsocondition power to be provided to the distributor 12.

In certain embodiments, a distributor 12 may include multiple coils 20a, 20 b, 20 c, each formed of several turns of an electrical conductor.When energized with current, each coil 20 may become an electromagneticcoil creating an electromagnetic field. A distributor 12 in accordancewith the present invention may also include one or more feedback devices22.

A feedback device 22 may provide information assisting the controller 14in controlling the distributor 12. For example, various types offeedback devices 22 may be implemented including human actuatedcontrols, detectors for detecting the presence of a user, temperaturesensors, current sensors, or the like. In selected embodiments, thefeedback devices 22 may insure safety, proper operation, limit dutycycles, and so forth.

In addition to controller feedback devices 22, a distributor 12 mayinclude user feedback devices 24. A user feedback device 24 may provideconfirmation to the user that the apparatus or distributor 10 isfunctioning properly. That is, a user without additional aids may beunable to perceive the electromagnetic field or fields being generatedby a system 10 in accordance with the present invention. Accordingly, asystem 10 may include one or more feedback devices 24 providing visualconfirmation of activity. Such devices 24 may include light-emittingdiodes (LEDs), displays, lights, or the like to encourage or sustain auser in his or her use of the system 10.

In selected embodiments, a controller 14 may include a processor 26operably connected to a memory device 28. A memory device 28 may storethe applications, programs, or code executed by the processor 26 duringoperation of the system 10. In selected embodiments, a processor 26 andmemory device 28 may collectively be embodied as a microprocessor.

In certain embodiments, a controller 14 may include a user interface 30receiving inputs from a user. For example, certain interfaces 30 mayinclude keypads, switches, knobs, buttons, touch screens, monitors, orother mechanisms for interaction with a user in generating electricalsignals to be received by a processor 26. Accordingly, a user may enterprogram parameters, timing information, duration information, frequencycontrol information, current information, or the like and therebyinfluence or control operation of the distributor 12. Likewise, a usermay select a particular intensity of electromagnetic field, frequencythereof, or the like. Alternatively, certain parameters may be“hardwired” into a controller 14 while others may be controlled througha user interface 30.

In selected embodiments, a user interface 30 may accept inputs that aremore qualitative then quantitative to a user. Such inputs may betranslated by a processor 26 into specific engineering and physics termsor variables suitable for implementation. For example, a user may inputselection of a long or short session. A user may input a request for aweak, medium, or strong intensity, and the like. Accordingly,preselected ranges may be programmed into the processor 26 in order tocomply with the user's qualitative requirements with quantitative datathat will be used by the processor 26 when controlling the distributor12.

A user interface 30 in accordance with the present invention may alsoprovide selected feedback or information to a user. For example, a userinterface 30 may include one or more displays. In certain embodiments,the operating conditions of a controller 14 may show in a display. Thedisplay may show simultaneously, sequentially (e.g., cycle through), oras instructed by a user any or all parameters. Parameters may includerepetition frequency, pulse current, duty cycle, magnetic field values,or other parameters of the system 10. A display may also show treatmentprogress, time elapsed, time to end of treatment, or the like, and mayinclude audio or other outputs to signal various stages of the session(e.g., the end of the session).

In selected embodiments, a controller 14 may include one or more controldevices 32. A control device 32 may implement the control functionsspecified by the processor 26 of the controller 14. For example, acontrol device 32 may include control circuitry (e.g., logic, switches,various relays, etc.) translating a control signal from the processor 26into an actual current delivered to a specific coil 20 of thedistributor 12.

A controller 14, through a processor 26, may dictate the currentwaveforms supplied to the coils 20 of a distributor 12. Parametersdictated by a controller 14 may include pulse repetition frequency,pulse amplitude, duty cycle of pulse current, duration of treatmentsessions, or the like. Such parameters may be fixed at the time ofmanufacture or be selectable by a user or treatment controller (e.g.,medical personnel).

Referring to FIGS. 2-3, an apparatus 10 in accordance with the inventionmay include several coils 20 each having a specified interior width 34as well as an exterior width 35. Typically, it is good magnetic designto maintain the interior width 34 as close to the exterior width 35 aspossible. Nevertheless, to be more comfortable for a user, it may bepreferable to distribute wires or cables further apart in order to avoida sensation or feel of too much weight or stiffness in a particular areaof the distributor 12.

Likewise, the coils 20 may each have an interior length 36 as well as anexterior length 37. The interior width 34 and interior length 36 mayestablish a flux window through which the magnetic flux of the coil 20passes. The dimensions 34, 35, 36, 37 of the coil 20, as well as thenumber of turns 38 of the coil 20, may be used to control the magneticstrength of flux generated by the coil 20. The current passing throughthe turns 38 of the coil 20 may also provide a degree of control overthe magnetic flux.

Accordingly, a window 40 or aperture 40 may represent the area filledwith the flux of the magnetic field generated by current through theturns 38 of the coil 20. In general, the coil 20 will extend in alongitudinal direction 42 and the lateral direction 44, corresponding,typically, to the width 34 and the length 36, respectively. Thus theflux through the aperture 40 or window 40 passes in the transversedirection 46 through the window 40.

As can be determined by the directional arrows 42, 44, 46, theillustration of FIG. 3 represents an end view of the coil 20 of FIG. 2.Thus, the direction of current flowing through the coil 20 or throughthe turns 38 of the coil 20 is illustrated by the arrow 48. Thedirection 48 of current controls, according to the respective laws ofphysics, the direction of the magnetic field 50 passing through thewindow 40.

Meanwhile, the depth 52 of the magnetic field 50 may characterize thestrength of a field 50 at a certain distance from the coil 20. That is,for example, the earth has a magnetic field that extends from pole topole and extends out through a large volume of space. Similarly, thecoil 20 has the ability to create flux lines 50 that extend far away.Nevertheless, at greater distances 52, the intensity or strength of theflux 50 may be less.

For example, near the actual wires forming the turns 38 of the coil 20,a very tightly turned flux 50 may be generated. Meanwhile, near thecenter of the coil 20, the flux lines may be substantially perpendicularor “normal” to the plane of the coil 20. While lines of flux 50 near theturns 38 themselves may close in a comparatively “tight” loop, the linesof flux 50 nearer to the center may extend a far distance before theyeventually turn back and enclose on themselves in a loop. Necessarily,the flux density out in that large expanse of space may becommensurately small.

By contrast, the flux density within the window 40 containing the sameamount of flux will be comparatively higher. Thus, the width 34 andlength 36 of a coil 20 may create a flux distribution of a desiredintensity within the window 40 and a desired intensity at a distance 52corresponding to the depth of a human body.

Referring to FIG. 4, in certain embodiments, when treatment iscommenced, repetitive current pulses may be transferred (e.g., throughcabling) to a distributor 12. A distributor 12 may include one or morecoils 20, typically one to six. The coils 20 may cover a significantportion of the distributor. For example, in selected embodiments, coils20 may consume about 60% to about 90% of the surface area of thedistributor 12.

In certain embodiments, the coils 20 may be connected in series. When soconnected, the overall effect is that the pulse current circulatesunidirectionally around the periphery of the array of coils 20. Thisensures that a patient or user will experience at least a minimum valueof the electromagnetic field, typically about 25% to about 30% of themaximum field produced in the middle of the user's body. Alternatively,coils 20 may be divided into sets of one or more, with each set beingsequentially pulsed. This may avoid the partial field cancellation thatmay otherwise occur when coils 20 (or the electromagnetic fieldsproduced by the coils 20) overlap.

In selected embodiments, each cycle of the current waveform may includean equal number of current pulses in each directions. This may permit adistributor 12 to be positioned easily, without any preferred orrequired orientation. Additionally, if any area of the body is moreresponsive to an electromagnetic field in one direction more than in theother, that area will receive adequate stimulation.

In one embodiment of an apparatus 10 in accordance with the invention, adistributor 12 may be formed as an article of bedding. For example, adistributor 12 may comprise a matrix 54 of fabric or similar materialssuitable for use as a blanket, mattress cover, layer within a mattress,or the like. The matrix 54 may provide a soft feel, warmth, or othersensory and tactile features desired by a user.

In selected embodiments, a matrix 54 may connect, stabilize, and securethe various coils 20 a, 20 b, 20 c, 20 d, 20 e. Since electromagneticflux 50 can directly interfere with and cancel other electromagneticflux, two conditions may be maintained with respect to the coils 20.First, the coils 20 may be set in a non-overlapping arrangement inspace. For example, the coils 20 may be positioned so as to besubstantially coplanar (e.g., distributed in a longitudinal direction 42along the matrix 54). Second, the coils 20 may be activated in anon-overlapping arrangement in time. That is, in selected embodiments,the controller 14 may ensure that no coil 20 is building, sustaining, orcollapsing an electromagnetic field 50 at the same time that anothercoil 20 is building, sustaining, or collapsing an electromagnetic field50. Thus, there is no interference between the coils 20 and no negationof the effectiveness thereof.

As a practical matter, the sequencing of energy delivery or currentdelivery to each of the coils 20 a, 20 b, 20 c, 20 d, 20 e may be in anysuitable sequence. For example, a strict sequential alternating betweencoils or from one coil to the next, adjacent coil may be appropriate.Likewise, a completely random distribution or sequencing between coils20 may be acceptable and provided by the controller 14.

Moreover, since the strength of an electromagnetic field 50 may bedependent upon the electrical current and the number of turns 38 in acoil 20, electrical heating may occur if the duty cycle for a coil 20 istoo high. It has been found that a duty cycle in the range of from about2% to about 10% is adequate. With variations in current, the duty cyclemay be manipulated. That is, for example, with a lower current the samemagnetic flux may be obtained with more turns 38 in a coil 20. Thus, thedynamic flux 50 desired through the aperture 40 of a coil 20 may bedesigned to control the heat losses and the appropriate duty cycle forthe apparatus 10, and for the individual coils 20.

Referring to FIGS. 5 and 6, one approach to sequencing the currentthrough the individual coils 20 may be to rely on a process 60 dictatedby the controller 14. For example, upon starting 62, the process 60 mayapply 64 power to the system 10. Thereafter, inputs may be received 66by the system 10. Such inputs may include any parameters used by theprocessor 26 in controlling operation of the coils 20 (e.g., times,durations, intensities, frequencies, currents, or other similar valueson a quantitative, qualitative, or comparable basis).

In accordance with the input received 66 or other pre-set instructionsor code, the controller 14 may apply 68 current to a particular coil 20.After a preselected time, or a calculated time based on other parameterssuch a flux density, current, and time, or the like, the controller 14may dictate removal 72 (termination) of the current from the coil 20.

Next, the controller 14 may advance 74 to the next coil 20 in thesequence. The controller 14 may then return 70 to application 68 ofcurrent to a coil 20, followed by a removal 72 of the current andadvancing 74 to the next coil 20. The cycle of applying current 68,removing 72 current, and then advancing 74 to the next coil 20 maycontinue for some period of time (e.g., a session duration), inaccordance with an appropriate duty cycle.

A duty cycle that is too great for a power supply 16 or for a coil 20may cause failure of the power supply 16 or overheating of the coils 20.Accordingly, power may be removed 76 from the system 10 betweenactivation of individual coils 20 for some extended period of time inorder to enforce a duty cycle. Alternatively, power may be removed 76from the system after cycling through all the coils 20 within thedistributor 12. In yet another alternative embodiment, power may beremoved 76 from the system 10 after a preselected or sensed number ofcycles of applying 68 and removing 72 current from the coils 20.

The end 78 of a treatment session may be controlled by time, or by a neteffective dosage of electromagnetic fields 50. For example, a user mayhave an exposure to higher field strength of flux 50 for a lower time orhave an exposure to a lower strength of flux 50 for a greater amount oftime. In certain embodiments, the field 50 or the flux density 50 andfield strength may not be changeable by user, and the time may be fixedat some appropriate amount of time (e.g., one to three hours). In otherembodiments, these parameters may all be changed and exchanged in orderto approach the therapy desired.

Referring to FIG. 6, a sequence 80 illustrates the generation ofmagnetic flux 50 consequent to applying current 68 to each coil 20 insequence. Accordingly, during a first time period, an electromagneticfield 50 may be generated from one coil 20 a. In a subsequent timeperiod, an electromagnetic field 50 may be generated from another coil20 b. In yet other subsequent time periods, electromagnetic fields 50may be generated sequentially or in turn from the remaining coils 20 c,20 d, and 20 e. Thus, FIG. 6 illustrates the application 68 of currentto a coil 20, followed by removal 72 thereof and advancing 74 to thenext loop 20.

Referring to FIG. 7, an alternative method 60 in accordance with theinvention may include additional optional steps with respect to thebasic process 60 of FIG. 5. For example, after application 64 of powerto the system 10, receipt 66 of inputs thereto, application 68 ofcurrent to a coil 20, and removal 72 thereof, the return 70 may includeadditional steps. A decision 82 may be made as to whether continuedtreatment is to be implemented. This may be accomplished in any suitablemanner.

For example, in one embodiment, a controller 14 may include a timerestablishing a therapy duration. The controller 14 may enforce thatduration by any mechanical, electrical, or electromechanical timer thatwill shut off current to the coils 20 after a specified duration. Forexample, a time period from about half an hour to about three hours maybe an adequate duration. Times up to ten hours may be effective.Nevertheless, for the use in stabilizing or reversing osteoporosis,between one and a half and two and a half hours may be a suitableduration.

Thus, at the end of a predetermined duration or by any other suitableparameter, the decision 82 may be made to continue or discontinue thepresent treatment session. If treatment is to be continued, anaffirmative answer may result in advancement 74 to the next coil 20.Alternatively, an affirmative answer may lead to an additional decision84 as to whether a cycle of all the coils 20 within a distributor 12 hasbeen completed. If a cycle of all the coils 20 has not been completed,then an advance 74 may occur, returning to the application 68 of currentto the next coil 20 in the sequence. Alternatively, if the cycle hasbeen completed, then a change 86 in the direction of current may beapplied.

Certain molecules in the cells of the body are dipoles. They act assmall bar magnets rotating to align with a magnetic field 50.Accordingly, it may be beneficial to change 86 the direction of currentand thus reverse the polarity of the magnetic field 50 induced by thevarious coils 20. A change 86 in the direction of the current applied toa coil 20 may be done on every alternate cycle, or after a number ofcycles. For example, the direction of current may be changed with eachcycle, or with every five cycles, every ten cycles, etc. as determinedto be most beneficial. Alternatively, each application 68 of current toa coil 20 may include application of current in both directions (e.g.,one followed by the other).

For example, current may be applied 68 at a step function 85, “on”followed by “off” followed by “on.” The direction of the current maythen be changed 86 and the step function 85 may continue. Alternatively,the current may be applied 68 in an alternating manner (e.g., in asinusoidal pattern 87) where the current transitions from a maximum peakin one direction to zero to a maximum peak in the opposite direction.When the current is applied 68 in such an alternating manner, there maybe no need to determine 84 whether a cycle has been completed, and theprocess 60 may simply advance 74 to the next coil 20.

When the decision 82 of whether a treatment session should be continuedis answered in the negative, application 68 of current to the coils 20may cease. If desired, certain data characterizing the treatment sessionmay be recorded 88, output 90, or both. In one embodiment, recording 88the treatment session data may include recording user identification,session duration, current or magnetic field strength, waveformcharacteristics, or the like.

Such data may assist in determining effectiveness of treatment andmonitoring whether the prescribed treatment has been completed. Output90 of session data may be provided to a centralized computer, printed,or simply displayed so that it may be logged by user patient.Accordingly, information characterizing a treatment session may be usedfor more general parametric evaluation of the efficacy of treatmentsover a broad population of patients. Finally, removal 76 of power fromthe system 10 or disconnection 76 of power from the system 10 results inan end 78 of the treatment.

Referring to FIG. 8, in various applications of medical treatments orother therapies, patient compliance is often a concern. Patientcompliance may be limited due to memory issues, confusion, fatigue, orthe like. Thus, everything from aptitude to attitude may affect theefficacy or the administration of any treatment.

Accordingly, a method 60 in accordance with the invention may providefor certain user-system interactivity that may aid in compliance. Forexample, in selected embodiments, a process 60 may include detecting 92whether a user is present. This may be accomplished by implementation ofa sensor of any several types. In one embodiment, a distributor 12 maybe installed on a bed as a mattress or mattress cover.

The distributor 12 may include one or more sensors using capacitance,contact, inductance, or the like to detect the presence of a user. Asimple pressure contact or capacitance change sensor may detect 92 thepresence of a user lying on the bed. When that presence is detected 92,the apparatus 10 may proceed to apply current to the coils 20.

By contrast, if a user is not detected 92, the apparatus 10 may enter 94a holding pattern and wait unit a user is present (e.g., enter 94 apattern of periodically polling one or more sensors to determine whethera user is present).

In some embodiments, a controller 14 may utilize an algorithm todetermine 92 whether a user is present in a manner suitable fortreatment. For example, a user sitting on a bed to put on a pair ofshoes, may not be suited for treatment. Accordingly, in selectedembodiments, both a particular time of day or night or a particularduration of presence may be required to move on within the process 60.Likewise, if a user is seated, it may be that only sensors near one ortwo coils may be activated. Accordingly, the controller 14 may determine92 that the user is not present for treatment. Thus, an algorithm mayassist in interpreting the various parameter indicating that a user ispresent, leading to a better decision 92 as to whether treatment shouldbegin or continue.

In selected embodiments, once the decision 82 has been made to end atreatment session, a system 10 may wait 96 for the next treatmentsession to begin. The duration of that waiting period 96 may depend uponone or more factors. For example, if a system 10 is dedicated to aparticular user (e.g., positioned on the bed of a particular user), thewait 96 may be preprogrammed by a delay time, time of day, or the like.

For example, a typical user will may undergo a period of therapy perhapsonce every evening (or every other evening) shortly after retiring.Accordingly, the wait 96 may begin with the end of one treatment sessionand end the evening of a later day. At that time, the sensors may beactivated, permitting the system 10 to again apply 68 current when it isdetermined 92 that a user is present.

Referring to FIG. 9, a distributor 12 may include one or more userfeedback devices 24. In certain embodiments, user feedback devices 24may be embodied as one or more light emitting diodes 98 (LEDs) arrangedon a distributor 12. The LEDs 98 may be configured in any suitablearrangement and be illuminated in any suitable degree, pattern,sequence, or the like.

For example, in one embodiments, LEDs 98 may be positioned along theborders of a distributor 12. The LEDs 98 may be illuminated by acontroller 14 whenever current is being applied 68 to the coils 20.Alternatively, certain LEDs 98 may be illuminated whenever to theoverall system 10 is powered, while other may be illuminated whenevercurrent is being applied 68 to the coils 20. In one embodiment, LEDs 98may illuminate only when the coil 20 most proximate thereto is receivingcurrent.

In selected embodiments, a distributor 12 may include one or moresensors 100 distributed throughout the matrix 54. In certainembodiments, the sensors 100 may all be identical. In other embodiments,an array of sensors 100 may include various sensors for differentparameters. For example, in selected embodiments, one or more sensors100 may represent a capacitance detector for pressure. Accordingly, if auser is present, then pressure on one side of a flexible capacitivesensor 100 may decrease capacitance and thereby indicate the presence ofa user.

In other embodiments, one or more sensors 100 may be simple contactsensors that indicate pressure as a digital “yes” or “no” (“on” or“off”) condition. In still other embodiments, one or more sensors 100may sense temperature, heart rate, inductance, or the like to detect,monitor, or otherwise provide information to the controller 14. In moresophisticated systems, a pulse, represented by either a repetitivemotion or cyclical pressure, or a temperature increase due to thepresence of a living person may serve to trigger a sensor 100 toactivate the apparatus 10.

Meanwhile, the insets illustrate alternative embodiments of the coils 20in accordance with the invention. For example, the orientation of thecoils 20 may be with their long direction extending in the longitudinaldirection of the distributor 12. Likewise, in certain embodiments, thecoils 20 may be circular. In other embodiments, the coils 20 may have anaspect ratio closer to one. That is, in certain embodiments, the ratioof width 34 to the length 36 of a coil 20 may approximate a value ofunity. In other embodiments, the ratio of the width 34 to the length 36of a coil 20 may be significantly less then one.

Referring to FIG. 10, an apparatus 10 in accordance with the inventionmay include a distributor 12 sized to fit a double bed (i.e., double,queen, king, etc.). The matrix 54 may be provided with coils 20distributed to be separately controllable between two individuals.Accordingly, one array may be aligned with one side of a double bed,whereas another array of coils may be aligned with the other side of thesame double bed.

In a simplified embodiment, both sides may be controlled at the sametime. Nevertheless, the embodiment of FIG. 10 illustrates one reason whyindividual controls such as those illustrated in FIGS. 7-8 mayefficaciously apply the electromagnetic therapy only when a user ispresent.

In one embodiment, an apparatus as illustrated in FIGS. 1-4 wasconfigured with the matrix being a blanket containing five coils. Theinterior width of each coil had a value of 18 cm and the interior lengthhad a value of 48 cm. Each coil included ten turns. The field strengthat 30 cm from the blanket surface, was controllable or presetable atfrom about zero to about 100 micro Tesla (uT), for an effective range offrom about 1 to about 100 micro Tesla. The duty cycle target was in therange of from about 5% to about 15%, depending on current flow, with atarget of about 7%.

Coils may be connected in series, so long as the direction of current isthe same in each, avoiding cancellation. Series connection, orindividually activated in sequence, they provided relatively uniformcoverage over the dimensions of a whole body covered by the blanket.Field cancellation was largely avoided. In one embodiment, additionalcoils were added around the periphery of the entire array of the fivecoils. The overall effect of the peripheral current in the peripheralcoil was about one fifth the field strength of the regular coils 20 at30 cm from the blanket.

Thus, even a simple series connection of the coils can provide a goodcoverage of the whole volume of the body with the difference betweenminimum and maximum exposure generally varying by less that about onethird.

Typically from about five to about twenty turns make a suitable coil,with ten to twelve turns forming a good design target. However, it wasfound that the turns per coil can realistically be varied from about oneto about 100 or even more with proper engineering. The magnetic fieldproduced is directly proportional to the product of current and numberof turns, a small number of turns requires a high current, whichrequires heavy duty circuitry and robust connectors, but a large numberof turns has a high resistance and so requires a high voltage and goodquality insulation.

From about 15 to about 60 volts may be preferable for safety, but manycountries use 240 volts, while the U.S. uses 115 volts (oftencharacterized as 110 or 120 volt outlet power). For not more than 50volts, a good compromise is around 10 turns per coil.

With respect to coil dimensions, the field of a circular coil ofdiameter D at a distance D normal (perpendicular) to the plane of thecoil, the field strength is about 45% of the field at the center of thecoil in the plane of the coil. With rectangular coils 60 cm×30 cm, thefield strength 30 cm from the center of the coil along its axis ofsymmetry is slightly above 50% of the field at the center of the coil.Thus dimensions of 60 cm×30 cm are adequate for good field penetrationand even distribution to a depth of at least about 40 cm. Coils 50 cm×25cm are adequate but might be regarded as the smaller end of the sizerange effective for full body exposure. However, they requireproportionately less current for the same field strength exposure.

In one engineered design, a single peripheral coil of from about 15 toabout 40 turns, having a (maximum) pulsed current from about 10 to about15 amperes provides about the same weight of conductor as a five-coildistributor. Fabrication is simpler, cheaper and field exposure is moreuniform. However, user perception has a psychological effect. A user maythink (incorrectly) that the absence of coils in the main area of theblanket is a disadvantage.

High frequencies such as radio frequency (RF) waves produce heating butno known, physio-chemical response in mammalian tissue. However, anapparatus and method in accordance with the invention induces currentsin circuits within its fields. Likewise, those currents distributevoltages across all elements of tissue circuits that conduct.Accordingly, all circuits that include bone cells as elements exposethat piezoelectric bone to a potential, e.g. voltage, inducing a stress(load force per unit area) and a strain (displacement length per unitlength), prompting a response by the organism. The stress, strain, andpotential appear to be consistent with exercise, and the physiology ofthe organism (e.g. person, animal) may respond as if it were. Thus,frequencies of from about 1 Hertz (i.e. low values, single digits orfractions) up to about 100 Hertz may trigger or otherwise couple withsuch physiological responses.

In addition, a mammalian body has immune and nervous systems havingchemical reactions that generate electrical signals. These may respondrepetitively at a communication frequency of from about 10 to about 100Hertz. On the other hand, a single response may often be triggered bypulses of much shorter duration. Thus, a repetition rate in the range offrom about 10 Hertz to about 1000 Hertz may rely on comparativelyshorter pulses.

A duty cycle in the range of 2 to 15% with the above pulse repetitionrates may cause a repetitive electrochemical stimulation in the bodysimulating use of parts by communicating as much, even without actuallyloading these tissues.

For stimulation effect caused by induced potential, the pulse shape maybe sharp, i.e. a square or rectangular pulse waveform, or acomparatively short duration sinusoidal waveform at frequenciescorresponding to bodily electrical functions. A very much slower rise isnot contemplated to be effective for this type of coupling.

A repetition rate of from about 100 Hertz to about 300 Hertz provides afrequency similar to that of the immune system, relevant bodymechanisms, or both, in vigorous exercise. It is contemplated that aduration of from about one half hour to about 2 hours per day. Arepetition frequency of 3 to 5 sessions (days of treatment) per week isconsistent with exercise rates known to be effective in maintaininggeneral health.

In one embodiment, a magnetic field of up to 100 uT may be supplied tothe bulk of a human body at a pulse repetition rate of from about 50 toabout 500 Hz. A duty cycle of over 1% and preferably from about 5% toabout 15% may ensure a magnetic pulse long enough for the bodyelectrochemical processes to be stimulated. A rectangular or rapidlyrising and falling current pulse shape or waveform from a large, singlemagnetic coil having from about 5 to about 50 turns extending around ablanket, proximate the perimeter thereof may serve well. Sequencingcurrent delivery to an array of from 1 to about 6 coils, each havingfrom about 5 to about 15 coils, and preferably about 10 turns each maycover the same area.

A treatment period may operate with power inputs greater than 1 VA, andtypically may draw from about 5 to about 10 VA of power. During eachcycle, the pulses may be reversed in a manner to provide about an equalnumber of magnetic pulses in the forward and reverse directions. Forthis and other reason there need be no requirement for any specificorientation of the blanket.

The frequency and field range provided by the coils of a distributor,such as one with a blanket or mattress pad acting as a matrix, may befixed or adjustable by a user or caretaker. It may also be regularlycycled, or timed by calendar or computer clock as to repetition ofsessions, or the like.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrative,and not restrictive. The scope of the invention is, therefore, indicatedby the appended claims, rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A method of increasing bone mass throughout thebody of a user, the method comprising: obtaining a distributorcomprising a blanket containing a plurality of coils, each coilconfigured to conduct electrical current and generate an electromagneticfield in response thereto; obtaining a controller comprising a processorand a memory device, operably connected to one another, the memorydevice storing code executable by the processor; selecting a source ofelectrical current; connecting the source to the controller; retiring,by a user, to a nightly bed of the user to sleep for a night;positioning the blanket over the user in the nightly bed; delivering,after the retiring and positioning, electrical current to the pluralityof coils, and controlling, by the controller in accordance with thecode, the delivering of electrical current sequentially and exclusivelyto each coil of the plurality of coils to generate an electro magneticfield extending therethrough and into the user.
 2. The method of claim1, wherein the plurality of coils are positioned adjacent one another ina non-overlapping arrangement.
 3. The method of claim 2, wherein eachcoil of the plurality of coils is positioned to be substantiallycoplanar.
 4. The method of claim 3, wherein the distributor furthercomprises a matrix comprising a flexible, breathable, material coveringand mechanically connecting the plurality of coils.
 5. The method ofclaim 4, further comprising positioning the distributor coextensivelyover an upper surface of a bed sized to accommodate the user duringsleep.
 6. The method of claim 5, further comprising triggering operationof the distributor in accordance with the presence of a user weightingthe upper surface of the bed.
 7. The method of claim 6, furthercomprising distributing, intermittently, by the controller, the currentamong to the coils for a duration of from about a quarter hour to aboutfour hours with, a duty cycle of actual current duration from about 1percent to about 15 percent.
 8. The method of claim 1, wherein thecontroller further comprises a sensor operably connected to provideinputs to the processor indicating the presence of a user proximate theplurality of coils, the method further comprising: sensing by the sensora separation of a user from the distributor; ceasing by the controllerthe delivering of current to the plurality of coils, in accordance witha first input from the sensor reflecting the separation; and resumptionof the delivering of current in response to a second input from thesensor reflecting a subsequent closure of the separation.
 9. The methodof claim 1, wherein the controller further comprises a sensor associatedwith the distributor to detect the presence of a user, the methodfurther comprising distributing by the controller the current to thecoils only during a period of time during which the sensor detects thepresence of a user.
 10. A method of treatment to increase bone densityin a mammalian subject, the method comprising: selecting a distributorcomprising a blanket containing at least one coil set in a matrix, theat least one coil configured to conduct electrical current and generatean electromagnetic field in response thereto; selecting a controllercomprising a processor and a memory device, operably connected to oneanother, the memory device storing code executable by the processor tocontrol delivery of the electrical current to the at least one coil;connecting the controller to a source of electrical current; retiring,by a user, to a nightly bed of the user to sleep for a night;positioning the blanket over the user in the nightly bed; delivering,after the retiring and positioning, electrical current sequentially toeach of the at least one coil to generate a magnetic field extendingtherethrough and substantially through the subject.
 11. The method ofclaim 10, wherein: the at least one coil comprises a plurality of coilspositioned adjacent one another in a non-overlapping arrangement; andthe coils of the plurality of coils are positioned to be substantiallycoplanar.
 12. The method of claim 10, wherein the matrix comprises aflexible, breathable, material covering and mechanically connecting theat least one coil.
 13. The method of claim 10, further comprising:positioning the distributor coextensively over an upper surface of a bedsized to accommodate the subject during sleep; sensing by a sensor thepresence of the subject on the bed; inputting to the controller an inputfrom the sensor reflecting the presence; and controlling by thecontroller operation of the distributor in accordance with the input.14. The method of claim 10, further comprising: providing a sensordelivering inputs to the processor indicating the presence of a subjectproximate the at least one coil; ceasing, by the controller, thedelivering of current to the at least one coil, in accordance with afirst input from the sensor reflecting separation of the subject fromthe at least one coil; and resuming, by the controller, the deliveringof current in response to a second input from the sensor reflecting asubsequent closure of the separation.